This invention relates to a method for synthesizing fluorocarbon fluids containing oxypentafluorotellurium (TeF.sub.5 O--) substituents. The TeF.sub.5 O-- group is inherently dense and when incorporated into fluorocarbon fluids it provides enhanced density to those materials. In addition, the ether-like oxygen link furnishes molecular flexibility, lessening of steric hindrances, and retention of fluid properties.
These fluids find particular utility as agents for a wide variety of industrial applications requiring the utilization of highly dense fluids. They are especially useful as flotation agents for gyroscopes, compasses and other like instruments which must be dampened to minimize excessive vibration and oscillation problems.
To the best of our knowledge, no previous examples have been reported in the literature incorporating the TeF.sub.5 O-- groups into fluorocarbons. Compounds containing the analogous sulfur substituent, SF.sub.5 OR.sub.f, are known, being mainly obtained by reactions of SF.sub.5 OCl and SF.sub.5 OF with olefins. This work showed that the addition of SF.sub.5 OX to olefins proceeded according to the general equation: ##STR1## For both of these hypohalites, good yields of the adducts are often obtained but the hypofluorite reactions are sometimes difficult to control and much lower yields are realized. This is not surprising in view of the fact that CF.sub.3 OF reacts explosively with some olefins and its addition to them is superseded by fluorination reactions.
In the case of SeF.sub.5 OF reactions with olefins such as CF.sub.2 .dbd.CF.sub.2, CF.sub.3 CF.dbd.CF.sub.2 and CH.sub.2 .dbd.CH.sub.2, no products containing the SeF.sub.5 O-- group were identified. With perfluorocyclopentene a good yield of the adduct, SeF.sub.5 OC.sub.5 F.sub.9, was obtained. No examples of the addition of SeF.sub.5 OCl to olefin have been reported.
Based on the observed trends in the reactivity of the Group VI hypofluorites with respect to olefins, one would expect that TeF.sub.5 OX, where X is F or Cl, should not undergo a facile addition reaction. Therefore, it was unexpected that the recently discovered TeF.sub.5 OF would react smoothly with olefins to provide TeF.sub.5 O-- substituted fluorocarbons in high yield by addition across the olefin double bond. Furthermore, it has been found that TeF.sub.5 OCl also adds to olefins. In this instance, the reaction is more difficult to control to achieve the desired addition, and yields of the adducts are lower. All of the TeF.sub.5 O-- substituted fluorocarbons are thermally stable fluids. Their either-like structure provides the desirable fluid properties exhibited by that class of compounds. In addition, they have enhanced density due to the presence of the TeF.sub.5 O-- group.